BMW Repair: my 323I shakes, mass airflow meter, vacuum leak

Question
My 2000 323I shakes hard when idling and the check engine light is on what would cause that ? It is also slower in acceleration and sluggish when up to speed !

Answer
Hello Brian,
It can be any of a number of things:
a) bad ignition coil   b) defective intake or exhaust cam sensor  c) defective mass airflow meter  d) defective 02 sensor  e) bad injectors  f) vacuum or air leak, even a crankcase vent valve vacuum leak that sucks oil into the intake manifold and causes misfires.
It would be ridiculous to replace each and every one of them
one by one just to find out which would correct the problem.
Even if one had the money, the time that would be wasted would be outrageous.
So nowadays we mechanics have scanners that read the stored fault codes and various other data streams in a vehicle
that help us arrive at a logical diagnosis. Scanners can be the top notch ones used by the car manufacturers/dealers,
moderately good scanners used by reputable independent shops, and mickey mouse scanners used by others.
You should have your car scanned to help diagnose you car.
Or as I have previously stated, do a trial and error kind of repair.
But there is one thing that I would recommend that you
verify, since irrespective of what defect you have right now, it still needs to be repaired/addressed. Removed the main upper engine cover and look at the ignition coils. If the brand is BREMI it needs to be replaced with BOSCH coils.
Chances are your current car problems are due to this if it still has BREMI coils. But then it could still be due to something else.
Regards,
Tino